Soap stock and process of making



Aug. 26, 1941, B. H. THURMAN 50A? STOCK AND PROCESS OFMAKING Filed March 19, 1938 Patented Aug. 2/6, 1941 SOAP STOCK AND PROCESS F MAKING Bronxville, N. Y., assigner Benjamin H. Thurman,

to Refining, Inc., Reno, Nev.,

Nevada a corporation of Application March 19, '1938, Serial No. 196,977

(Cl. 26o-4:25)

7 Claims.

This invention relates to soap stock and process of making, and more particularly to a process of refining vegetable .oils so as to produce an improved soap stock while reducing refining losses and also producing an improved raw oil as an intermediate product in the process.

The soapv stock now produced in refining vegetable oils contains large amounts of impurities, such as phosphatides, proteins and other nonfatty material. It is extremely difficult to purify such soap stock so that it may be incorporated into commercially acceptable soaps or otherwise used. According to Lewkowitsch the average composition of cottonseed soap stock is as follows:

Percent Fatty anhydrides 48.50 Glycerine 3.98 Caustic soda (Na20) 3.20

. Foreign organic matter 5.90 Water 36.00 Coloring matter 2.42

Such a mixture cannot be kept in storage for any length of time or shipped without fermentation and decomposition. It has heretofore been attempted to use this material by sub-'- jecting it to washing and graining out processes similar to those used in the conventional kettle soap making processes. Such processes are expensive and time consuming, as several washes 1000 pounds of soap stock having a 50% fatty .acid content, 100 pounds of solid, 76% caustic soda, and 100 pounds of salt are required to produce '750 pounds of settled soap. v

As further stated by Thomssen 8a Kemp, the soap thus produced is soft bodied and has a characteristic and disagreeable odor. Itis quickly soluble, but produces a thin, slimy lather. The use of such cottonseed soap stock is limited to soap powders and similar preparations.` Such products seldom contain more than ,25%, soap, as large amounts of soda ash and other filling materials are used. to disguise the odor, hide the colorv and serve to preserve the soap. Little, if any, bar soap is made from soap stockatthe present time.

Soap stock is, in many cases, treated with sulfuric acid, to decompose the soap and liberate fatty acids, and also is treated with splitting reagents, such as Twitchell reagents, to split any glycerides present to further liberate fatty acids. The liberated fatty acids are then distilled, leaving a residue containing a large percentage of the fats. This lresidue is like tar or pitch and is useless waste material. In addition, some of the impurities distill over with the fatty acids, which necessitates at least a second distillation to produce fatty acids of suii'icient purity for making commercially acceptable soap. .'This also is an expensive and time consuming proposition and results in wasting a large percentage of the soap stock.

In accordance with the present invention, oils such as. cottonseed, soya bean, corn, rapeseed and linseed, are rened by a process which produces a soap stock substantially free of odorous impurities and those which readily ferment and decompose, at the same time the refining losses are reducedfmarkedly over those occasioned in conventional refining processes. Also, an improved raw oil is produced as an intermediate product which, if drying oils, such as linseed or soya bean, are Abeing refined, may be sold as a semi-refined or non-break raw oil.' Minor constituents which constitute deleterious impurities in the soap stock are recovered separately from the soap stock, and since these minor con- 'provide an improved refining process for vegetable oils by which a relatively pure soap stock capable of being directly incorporated into high quality soaps is produced.

- Another object of the invention is to provide a process of refining vegetable oils in which phos phatides are recovered as a valuable by-product separately from the soap stock..

Another object of the invention is to provide a process of `refining vegetable oils in which oils` having non-break characteristics may be produced.

. Another object ofthe invention is to provide a new and improved soap stock product.

In carrying out the present invention, the

vegetable oils being reiinedare subjected to a two-stage process. In the rst stage, the odorous materials and those which readily decompose and ferment, are substantially completely removed prior to contacting the oil with the usual alkali refining reagent. By employing a suitable precipitating reagent, substantially all of such materials can be removed in a single operation so as to produce a non-break oil. That is, an oil in which no substantial darkening of the voil or precipitation of foots will take place if the oil is heated to 600 F. Also, by employing a precipitating reagent which has preservative properties, the crude phosphatides thus removed may be stabilized against fermentation and decomposition. The entire process is preferably carried out as a continuous operation.

Batch precipitation with either settling or centrifugal separation of impurities has heretofore been proposed, but large losses were -occasioned therein and the percentage of -precipitating reagent Was critical. Also by these suggested processes it was not possible to substantially completely remove the ingredients which result in fermentation vand decomposition ofthe soap stock produced by subsequentl ening. Fur-V thermore, the thus purified oil was diicult to refine as the long time of heating in the batch mixing process tendedvto set the colors in the oil. Batch refining of oil resulting from either batch or continuous precipitation and separation treatment is not practicable, as the soap stock settled from the oil entrains large amounts of neutral oil, thus producing excessive refining losses. Such soap stock is a loose occulated material because of the reduction of the amount of non-fatty impurities therein and will not settle compactly from the refined oil.

In accordance with the present invention, the oil is substantially completely denuded of the constituents which are deleterious in thesoap stock. This is done in a continuous operation effected in a very few minutes such that the oil is not subjected to lengthy heating. The co1- ors are not set and, if desired, suicient of the constituents are removed so as to produce, prior to complete refining, an improved oil having non-breaking characteristics. 'I'he treated oil may then be substantially immediately contacted with an alkaline refining reagent as part of the same continuous process and quickly thereafter centrifuged to separate the soap stock from the refined oil. The heated oil from the precipitation and separation operations is preferably utilized .promptly in the alkali refining operation so that the oil is not subjected to two separate heating operations. It is advantageous to maintain the oil out of contact with the air While all losses are reduced below. that of known refining processes.

Other objects and advantages of the invention will appear in"` the following description of the invention, which is made in conjunction with the diagrammatic drawing of an apparatus suitable for carrying out the process and shown on the attached drawing.

Referring to the drawing, a source of supply for the oil to be treated is shown as I0. source of supply for a phosphatide precipitating reagent is shown as a tank II. Proportioning pumps I2 and I3 for oil and reagent, respectively, may beemployed to withdraw oil and reagent from the tanks I and Il, respectively, and deliver these materials through pipes I4 and I5 to a flow mixer I6. The proportioning pumps I2 and I3 may be driven by a, variable speed motor I1 with a variable speed device If8 positioned between the pumps so that any desired amounts and proportions of oil and reagent may be delivered to the mixer I6. The particular proportioning mechanism disclosed is shown merely by Way of example, and any other suitable type of proportioning device which will deliver proportionedstreams of oil and reagent to the mixer I'G may be substituted therefor.

The mixer I6 may be any suitable iiow mixer,

such as a device in which a stream of one of the materials is injected at right angles into the stream of the other, or may be any suitable mechanical agitator. The oil and reagent are. thoroughly or intimately mixed in the mixer I6 and constituents, including phosphatides, proteins, etc., are precipitated to render them capable of being centrifugally centrifuged from the oil. Such centrifugal separation can be more effectively carried out at elevated temperatures since in a heated condition, and therefore, the present invention contemplates employing a closed system from the point of entrance of the oil into the precipitating step "to Aits discharge from the process as rened oil.

It is, therefore, an object of the invention to provide a continuous process 'of removing materials which constitute deleterious impurities in soap stock and then alkali-refining vegetable oils. Another object of the invention is to provide a rapid process of iirst removing phosphatide constituents and then the free fatty acids from vegetable oils ir. which the oil is maintained` out of contact with the air during such process.

A further object of the invention is to produce a stabilized or preserved phosphatide material. A still further object of the invention is to provide a continuous process of purifying and alkali refining vegetable oils by Awhich the overa diiiicultly separable emulsion tends to form when the oil and reagent are admixed. It is,

therefore, desirable for effective separation that the mixture of oil and precipitated material be separated at an elevated temperature, and this temperature can be attained by preheating the oil by passing the same through a heating device shown as a coil I9 positioned in a heating Jacket 20 through which any desired heating medium,

4such as hot water, steam or heated oil, may be circulated by the pipes 2I and 22.

Alternatively, mixing can be performed at a relatively low temperature and the mixture heated by passing the same through a heating device shown as a coil I9 positioned ina heating jacket 20' through which vany desired heating mediumcan be circulated bythe pipes 2l and 22'.` Also,\both the heating devices I9 and I9' lcan be employed, each furnishing part of the heat necessary for separation, or either one can be eliminated depending upon the type of oil being treated. In any case, the heated mixture is delivered through a pipe 23 to a continuous centrifugal separator 24 from which the precipitated materials are discharged 'as a heavy emuent through the spout 25 into a receiver 26. The oil is discharged as a lighter eilluent through a pipe 21. While the oil thus discharged may be conducted directly to the alkali refining treatment stage, it is sometimes desirable to provide a small reservoir in order to insure a constant flow of materials through tl'e. alkali treatment atmosphere into the tank 28.

tion of the materials removed by the present proccontact of the heated oil from the centrifuge 24 'with the atmosphere, the tank 28 may be provided with a water seal, for example, a closed tank 29 and an open tank 30. The tanks 29 and 30 may contain water or other sealing'liquid and the tank 28 is connected to the tank 28 by a pipe 3| terminating above the surfaces of the liquids in these tanks, while the tank 30'may be connected to the tank 28 by a pipe 32 terminating below the surfaces of the liquid in the tanks 29 and 38. By such an arrangement, or its equivalent, the oil level in the tank 28 may vary without causing air to be drawn from the In many cases it is desirable to hold the tank 28 under vacuum tenet only exclude air from contact with the oil but to also remove air which may be present in the oil. Also, with certain oils, the tank may be open to the atmosphere, in which cases the provision of 'such a seal is not necessary. If itis desired to withdraw the purified oil to be employed or'sold, such oil can be withdrawn, for example, from the tank 28 through the pipe 33. Thus the present invention can be employed to' produce a non-break drying oil which can be, if desired, further treated, for example, by vacuum drying, or washing and vacuum drying, in order to produce an acceptable com'- mercial oil.

To remove the free fatty acids in theoil delivered to tank 28, this oil may be withdrawn by a proportioning pump 34 and delivered through a pipe 35 and heat exchange coil 34' provided with a casing 35' through which any desired heating or cooling medium may be circulated to a flow mixer 3B. An alkali refining agent may be withdrawn from a source of supply 3l and delivered by proportioning pump 38 through a pipe 39 to the mixer 36. 'I'he proportioning pumps 34 and 38 may be of the same type as the proportioning pumps i2 and I3 and may also vbe driven by a variable speed motor l1 with a variable speed device I8 positioned between the pumps 34 and 38, or any other suitable proportioning mechanism for delivering accurately proportioned streams of 'oil and alkali to the mixer 36 may be employed. The mixer 38 may be similar tothe mixerni, thus, it may be a device for injecting a stream of one material into a flowing stream of the other, or it may be any suitable type of mechanical agitator. The alkali contacting the oil in the mixer 36 substantially instantaneously neutralizes the free fatty acids therein to form soap stock.

Since it may be desirable to separate the soap stock formed in the mixer 38 at a higher or lowerv temperature than the mixture coming from the mixer. 36, a heat exchange device, shown as a coil 40 positioned in a jacket 4! through which any desired heating or cooling medium may be circulated by means of pipes 32 and 43, may be employed to adjust thetemperature of the oil entering the continuous centrifugal separator 44 for continuously separating soap stock from rened oil. The soap stock is discharged asa heavy effluent from the centrifuge 44 through a spout 45 into a receiver 46, and reflnedtoil is discharged as a lighter eiiluent through the pipe 41 vinto receiver 48. y

It has heretofore been known that water alone or water containing Very small amounts or traces of variousreagents will precipitate impurities from vegetable oils. However, in general, water alone or water with such small amounts of reagentsA will precipitate only a very small por- Cil ess. In accordance with the present invention, precipitating reagents are employed in water solutions of suflicient concentration to substantially completelyl precipitate the constituents which cause breaking of the oil and give the soap stock deleterious properties. Boric acid is one preferred reagent, and applicant has found.

that a 10% solution of boric acid employed in proper proportions will precipitate substantially all of such constituents, although this concentration may be varied somewhat with different oils. The boric acid is a preservative for precipitated materials and is discharged in thorough admixture therewith from the centrifugal separator. The thorough admixture of the preservative with. the separated material is' important, -since it is diicult to mix a preservative agent with this material after it has been separated, as it then is characterized by being a thick, viscous mass. 'I'he employment of boric acid also enables the subsequent employment of the separated constituents as phosphatides for edible pur-- poses, either in the form in which they are discharged from the separator or after purification.

Other reagents may be used for precipitating the phosphatides and non-fatty constituents from the oil and in` general electrolytes which have no substantial deleterious reaction upon the oil being refined can be employed. Thus certain acids, alkalies and salts may be employed. Even are employed they should be suiiiciently diluteto prevent substantial attack upon and saponification of the neutral oil. Weak alkalies, such as sodium silicate, trisodium phosphate and triethanolamne, may be employed in approximately 10% concentration. In any case where alkalies or alkaline salts are used, the amount of reagent employed is insumcient to saponify any substantial quantities of the free fatty acids. Substantially neutral salts, such as sodium sulfate, sodium berate, sodium chloride and zinc chloride may also be employed in relatively concentrated solutions in order tothrow the impurities out of the oil solution. Certain of these materials, for example sodium silicate and zinc chloride, also act as preservatives of the phosphatides. The'reagent selected will depend upon the type of oil being treated and thecontemplated subsequent use of the precipitated and diiiicultly separable emulsion between the oil and AWater during the prolonged 'agitation necessary for adequate Since suchcvpr'olonged agitation is not employed in the present process,

it is possible and also extremely desirable to use.. considerably more,v precipitating reagent than p could be employed in batch mixing steps. Thus, quantities ranging from 2 to 5 times greater than paragraph.

that which would be normally used in the kettle or batch method' are contemplated.

Hot vegetable oils containing free fatty acids will form large amounts of foam when mixed with air in the entrance and discharge passages of a centrifugal separator, thus interfering with separation, which was one of the diculties encountered when attempts were made to centrifugally separate the material precipitated in a batch or kettle mixing step. The larger amounts of reagent of the present process sufficiently wet the oil to prevent the oil from foaming during centrifugal separation. Also, the larger amounts of reagent and the resultant wet mixtures are effective to materially reduce entrainment of free oil with the separated material so that losses are markedly reduced. Furthermore, such larger amounts of reagent soften the precipitate so that it will not adhere to the walls 'of the centrifugalv bowl. This adherence of the precipitated material compels frequent cleaning of the bowl and heating. Also the precipitating reagent may be heated in the tank Il before introducing the results in ineffective separation in the prior processes referred to. In the present process, therefore, suicient reagent should be employed to wet the oil so as to prevent foaming during centrifugal separation, prevent substantial entrainment of free oil in the precipitated material separated from the oiland prevent adherence of the precipitated material to the walls of the centrifugal bowl.

yin the process.

same into the process by any suitable heating arrangement, such as a heating coil or jacket (not shown). This step is of particular importance when the precipitating solution is substantially saturated at the temperatures employed For example, the 10% solution of boric acid above referred to must be kept at a temperature of approximately 150 F. to prevent crystallization of boric acid. By preheating both the oil and precipitating reagent and preventing the temperature from dropping below 150 F. during the precipitating operation, such crystallization can be prevented. With other precipitating reagents ythe temperature may be somewhat lower and subsequent heating employed instead of preheating.

As before stated, a portion of the constituents separated by the present process can be precipitated by the employment of water alone, but large amounts of them will remain in the oil so as to appear in the resulting soap stock and also vcause the oil delivered from the centrifuge 24 An exact numerical amount of. precipitating reagent which should be employed in the present ,process applicable to alll oils can not be given,

as the amount will vary with different oils, increasing with the amount of phosphatides and non-fatty constituents contained therein. The amount of these constituents apparently varies according to the amount of4 decomposition which has taken place in the seeds from which the oil is obtained. That is, in general, the amountsitating reagent. For oils containing verysmall amounts of precipitatable material, 1% of reagent may be sufficient, while other oils mayrequire as much as 10%. In any event, the amount of precipitating reagent should be sufficient to precipitate the phosphatides and non-fatty matter and wet the oil as discussed in the previous The optimum temperature of separation vary with different oils, but, in general, will lie between 100 and 160 F., although with some oils temperatures somewhat below this range may sometimes be employed. The important consideration is that the mixture be at an emulsion breaking temperature during centrifuging and for this reason it is possible to preheat the oil or both the oil and the precipitating reagent prior to admixture. Thus, a heating device similar to I9 can also be inserted in the pipe lli.v Since, in

such an operation, the oil is rapidly heated, and.

almost immediately thereafter separated from the resulting foots and then promptly alkali refined, no setting of the color in the oil is caused as is the case in batch processes involving preto be a break oil. Since water is conventionally employed in the cooking operation prior to expressing vegetable and animal oils, a portion of these constituents are usually in an already precipitated state such that merely heating the oil and centrifuging the same'will result in the separation of a portion thereof. In this case also large portions of these constituents remain in the oil `from the centrifuge 24.

The preferred alkaline reagent for neutralizing the free fatty acids is an aqueous solution of caustic soda, but other alkalies, such as caustic potash, sodium carbonate, trisodium phosphate, etc., may be substituted therefor. The alkaline refining reagents are employed in amounts sumcient to completely neutralize the free fatty acids and ordinarily providedan excess for reaction with any minor constituents which remain in the oil. 'I'he excess 'will also cause removal of coloring matter with the soap stock if caustic alkalies are employed. The amount and concentration of alkali refining reagents addedto the oil will vary` with the free fatty acid content thereof and the type of oil being refined,v and no precise proportions can be given. The concentrations known to be suitable for refining a given oil will, in

general, be found suitable, but a somewhat smaller excess can usually be employed, as the phosphatides and other minor constituents which also react with alkalies have been previously removed. There is thus less opportunity for the saponification of neutral oil, resulting in lower losses.

Also a saponiflcation and entrainment inhibitor form an emulsion. Either coil 34' or 40 or both may be employed to furnish any additional heat which may be necessary to provide such temperature and if desired a similar coil may be employed to preheat the refining reagent from the tank 31 in order to obtain 'a' desired temperature of mixing. If the oil in tank 28 or delivered directly from the centrifuge 21 to the proportioning pump 34 is at the requisite temperature so that a mixture with the refining reagent is produced in eliminated, although in many cases it is desir-` able to provide a short time of contact between the alkali and oil prior to centrifugal separation in order to condition the soap stock for centrifugal separation. In the latter case, the coil 40 may be retained for that purpose, even if no heating or cooling is performed therein. If it is found advantageous to separate at a somewhat lower temperature than the temperature of mixing, the coil 40 may be employed to cool the mixture. With certain oils, it has been found desirable to employ the coil 34 to cool the oil to a temperature below that desirable for centrifugal separation, for example to '70 or 80 F., then mix the oil with the alkali and subsequently heat the mixture to an emulsion breaking temperature.

The emulsion breaking temperatures employed for centrifuging soap stock from the oil will vary with the type of oil being refined and the amount of free fatty acids therein, such that no precise temperature can be stated which is applicable to all oils. In general, this temperature will fall between 100 and 160 F., although in certain cases temperature somewhat above orbelow this range may be found desirable. The centrifugal devices employed may be of any suitable type capable of separating precipitated 4material or soap stock from animal and vegetable oils, but the heated centrifuges disclosed in the Patent No. 2,100,277 to Benjamin Clayton are preferred, as a more uniform discharge from the separators is produced thereby.

As previously stated, the soap stock formed by mixing an alkaline refining reagent with an oil containing free fatty acids but substantially no phosphatides or other non-fatty material can not be economically separated from the oil by a batch settling step, because of the entrainment of oil therein. However, the continuous centrifugal separation step of the present process hasbeen found to effectively separate the oil from such soap stock without substantial entrainment of oil therein. In the process above described, the oil flows as a substantially continuous `stream throughout the process, and sufficient movement of the mixtures, produced by adding either the precipitating reagent or refining reagent to the oil, is maint-ained to preventstratification of the resulting foots from the oil prior to centrifuge, l

so that substantially uniform mixtures are delivered to the centrifugal separators. The entire process can be carried out within afew minutes, for example the oil and precipitating reagent can be mixed substantially instantaneously, or if agitators are employed, such agitation can be ca'rried on for substantially less than five minutes. Centrifugal separation of the precipitate from the oil is a rapid process involving not more than two to four minutes. The oil may remain in the tank 28 for as short a time as two minutes, or if necessary', can remain in such tank for periodsA upwardly of fifteen to twenty minutes. The times of mixing, heating and centrifuging in the final refining operation may be substantially equivalent to those employed in the precipitating operation, such that the entire process may be carried out in as little as ten to fifteen minutes,

' although in certain cases4 with oils which are difficult to process, the time for the complete operation may extend as long as thirty minutes. Ap-

p-roximately the same time or a shorter time for the complete process is also possible where preheating of the oil or reagent, orlboth, is ernployed as above described. Since the oil is maintained in a heated condition for a short time only,`

the color is not set in the oils and no deterioration of the oil results. In general, a lighter colored oil is produced by the present process than by refining processes in which the free fatty acids and non-fatty materials `are concurrently removed. Also, the maintenance of the oil out of contact with the air or substantially out of contact with the air during the entire process prevents deterioration of the oil.

As a specific example of the present process as compared with present day continuousV refiningl processes, two samples of the same oil were treated in commercial size apparatus, the first sample being subjected to straight refining and the second sample being first treated to remove phosphatides and non-fatty matter and then refined under the same conditions as the first sample.

The oil selected was a very good grade of cottonseed oil containing only 0.64% free fatty acids and relatively a small amount (less than 1%) l of phosphatides and non-fatty matter. Such an oil best illustrates the advantages of the processm as it is difficult to demonstrate an improvement y over even conventionalbatch refining, as the losses are relatively small'and a relatively goed soap stock is produced in any event.

The first sample was lrefined by continuously mixing proportioned streams of oil and -alkali at F., the pressure in the mixing zone being 150 Y pounds per square inch. The amount of lye employed=was 3.3% of 14 B. sodium hydroxide and the resultant mixture was passed through a series of three heating coils at 120 and 130 F., and then directly to the heated centrifuge above mentioned, in which steam was in contact with the bowl. Soap stock and a good grade of refined oil were continuously discharged as separate efliuents. The refining loss in this process was 5.1% as compared with 6.04% obtained by the official cup test.

The second sample was subjected to the process of the present invention by preheating the oil to a temperature of .160 F. and then mixing the Same With 1/z% of a 10% boric acid solution. The mixture was passed through two coils at a temperature of F. and then the precipitated material separated from the oil in a heated centrifuge. The loss resulting from this portion'of the process was 1.00%. The material separated -from the oil contained a large percentage of phosphatides and substantially all of the boi-ic acid solution, which acts Vas a preserving agent therefor. This material can be emploryed as a phosphatide material even in edible products, or can be easily purified to produce substantially pure phosphatides. The resultant oil was substantially free of phosphatides and nonfatty matter (less than 0.1%) and also had its free fatty acid content reduced to 0.48%. This oil was then cooled to 75 F. and refined in exactly the same manner and with the sa e pro;- portions and concentration of alkali4 solution as the first sample. The refining loss in the refining step of the second sample was 3.3% which, added to th 1.00% loss in the first step, gives a total refining loss of 4.3% as compared to 5.1% refining loss for the continuous refining of the The soap stock produced by continuous rening alone and by the present process had the following analysis and properties:

Physial characterisl Viscous, pasty, browntics of soap stock.

ish black mass; foul, putrefactive aminelike odor which becomes more pro nouncedonstanding; ferments and putreiles rapidly.

Balls of soap, dark brown in color and having pungent amine-like odor which persists on standing.

Viscous, light brown mass; practically odorless; no foul or aminedike odordevelops on standing.

Physical characteristics of soap produced.

Granular,lightbrown and odorless; no odor develops on standing.

It will be noted that the phosphatides and nonfatty organic matter present in the soap stock was reduced from 5.82% to 0.69%. As pointed out above, a high grade crude cottonseed oil containing only small amounts of phosphatides and non-fatty matter (less than 1%) was employed, such that the amount in even the soap stock from the straight rening process was relatively small. In general, the amount of phosphatides and non-fatty organic matter in the soap stock from straight refining will range from 5% to 10% or higher. Even with crude oils containing relatively large amounts of such materials, the present process produces soap stock containing only small amounts comparable to the 0.69% of the present example, i. e., soap stock containing less The unstable non-fatty organic compounds were removed during the process. It will be further noted that the nitrogen content of the soap stock is greatly reduced, as is the protein content which was calculated from the nitrogen content. Nitrogenous compounds are, to a large degree, responsible for the foul odor, discoloration, and

tendency toward putrefaction of ordinary soap stocks. It is evident that the small amount of nitrogenous compounds in the soap stock of the present invention is relatively stable.

The soap stock from both the straight refining process and the present process was converted into soap by adding suicient sodium' hydroxide solution to saponify the neutral oil present and heating. 'I'he soap was salted out and washed several times imth water and then dried and powdered. The physical properties of the soap are given in the above table. It will be noted that the soap stock of the present invention produced a granular soap which was odorless and light brown in color. Whereas the soap stock from straight refining was not granular and had a dark brown'color and pungent amine-like odor.

Thus the soap stock-producedis substantially odorless and is of light color and can be converted into odorless light colored granular soap. Also the materials separated from the oil by the centrifuges 24 and 44 respectively contain reduced amounts of neutral oil, such that refining losses due to entrainment of neutral oil in the separated material is markedly reduced over conventional processes. The precipitating reagent is either of a nature which will notattack the neutral oil or is employed in sufficiently dilute concentration and amounts to prevent attack of the neutral oil. The oil from which the precipitated materialhas been separated can be treated with an alkaline rening solution by the continuous refining step and the neutral oil substantially completely separated from the resulting soap stock. Such oil can not, however, be economically refined by batch or kettle refining involving settling of the soap stock from the oil, since the settled soap stock entrains large amounts of free oil. 'I'he soap stock resulting from the present process is substantially free from fermentable and readily decomposable materials and can be incorporated directly into high quality soap products either in bar or powdered form in amounts of approximately 40 to 60% or greater. 'I'he soap product thus produced is substantially free of materials which will cause decomposition and deterioration of the soap.

The refined oil discharged from the centrifuge 44 may be treated with any conventional and well known clarification or bleaching step, such as washing and vacuum drying or treatment with absorbent clays and filtering, and such steps can be carried on as part of the continuous process. The process has been described in conjunction with vegetable oils, but is applicable to any type of glyceride or other fatty oils presenting the same problems.

While I have disclosed the preferred embodiments of my invention, it is understood that the of the following claims.

What I claim is:

1. The continuous process of treating vegetable oil containing phosphatides, non-fatty matter and free fatty acids, comprising the steps of, mixing a stream of yan aqueous solution of a reagent which will precipitate said phosphatides and non-fatty matter with a stream of said oil insufficient amount and concentration to substantially completely precipitate the same without destruction of said phosphatides or said oil, promptly continuously centrifugally separating the precipitated material from the oil, promptly mixing a stream of an alkaline refining reagent with a stream of the resultant oil in suiiicient amount and concentration to substantially completely react with the fatty acids therein to form soap stock, and promptly thereafter centrifugally separating said soap stock from said oil to produce a substantially pure soap stock.

2. The continuous process of treating crude glyceride oil containing phosphatides and free fatty acids, comprising the steps o1', mixing a stream of a. precipitating reagent which will precipitate phosphatides without destruction of said phosphatides or said oil with a stream oi' said oil, promptly continuously centrifugally separating the precipitated phosphatides from the oil, promptly thereafter mixing a stream of an alkaline refining reagent with the separated oil 'in suflicient amount to react with substantialw `stream of alkaline refining reagent with said all of said free fattyl acids to form soap stock,

and thereafter promptly continuously centrifu-` gally separating said soap stock from said oil.

3. The continuous process of treating glyceride f oils containing free fatty acids and non-fatty matter, which comprises the steps of, mixing a stream of an aqueous solution of. a reagent which will precipitate said non-'fatty matter with a stream of said oil in suilicient Jamount and concentration to precipitate substantiallyall of the non-fattygmatter contained in the oil without destruction of said nonffatty. matter or said oil,

promptly continuously centrifugally separating the. precipitated non-fattymatter from said oil, promptly mixing a stream of an aqueous alkaline solution with a stream of the resultant oil in sufficient amount to substantially completely neutralizaxv said free fatty acids, and thereafter promptly continuously centrifugally separating l the resulting soap stock from said oil.

4. Theprocess of treating crude glyceride oils` containing free 'fatty acids and minor constituents including phosphatides, which comprises the steps of, mixing an aqueous solution of a precipitating reagent in sufficient amount and concentration to precipitate substantially. all of said minor constituents, promptly centriiugally separating the precipitated material from said oil whileV the same is in a heated condition, promptly thereafter mixing an alkaline refining reagent with the heated oilin suillcient amount to react with substantiallyl all of the free fatty stream of heated oil in sumcient amount` to substantially completely neutralize said free fatty acids to form soap stock, and promptly centrifugallyl separating said soap stock from said oil at an emulsion breaking temperature so as to produce separate streams oi refined oil and soap stock substantially free of said 'non-fatty material. f

(i.I vThe process of treating crude vegetable oils containing free fatty acid and non-fatty material, which comprises, continuously mixing a stream of said oil with a stream of a precipitating reagent so as to' precipitate non-fatty material to render the same 1 separable from said oil, promptly delivering the resultingmixture to a centrifugal separator and continuously separating the precipitated material from said oil at an emulsionbreaking temperature so as to deliver separatev streams of foots and heated oil from said separator, promptly thereafter mixing a stream of alkaline refining reagent with said stream of heated oil in sufficient amount to substantially completely neutralize said free fatty acids to form soap vstock from said oil at an emulsion breaking temperature so as to produce separate streams of rened oil and soap stock substantially free of said non-fatty material, 'the process being carried out in. a closed system whereby the oil is maintained out of contact with air vwhile in admixture with said reagents and` i in a heated condition.

acids to' form a soap stock substantially free from said minor constituents, and thereafter promptly separating said soap stock from said oil whilel the same is in said heated condition.

5. The pr'ocess of vtreating crude vegetable oils containing free fatty acids and non-fatty material, which comprises, continuously mixing a stream of 'said oil with a stream of an aqueous 7. A quick and continuous process for treating ,vegetable oils containing gums, which comprises the steps of: continuously admix'ing a precipitatprecipitating solution so as to precipitate nonfatty material to render the same separable from said oil, promptly delivering the resulting mixture to a centrifugal separator and continuously separating 'the precipitatedl material from said.

oil at an'emulsion breaking temperature so as to deliver separatestreams of ioots and heated oil from said separator, promptly thereafter mixing a ing reagent of a character and amount suiiicient to precipitate said but without substantially reacting with the free fatty acids contained therein: promptly, before inlury tothe oil,y continuously centrirugally separating the precipitated gums from said oil; promptly con.-

tinuopsly mixing a neutralizing reagent with the thus degummed oils in suiiicient amount to substantially completely neutralize the free fatty acids remaining therein and to .form foots and.

promptly continuously centriiugally separating the foots from the thus rened oil.

BENJAMIN H. 

